This invention is related to systems for mixing bulk quantities of windshield washer liquid and more particularly to a system for mixing bulk quantities of windshield washer liquid for both cold and warm climates that allows the system to be quickly and easily switched between producing a cold weather formulation and a warm weather formulation of windshield washer liquid.
Windshield washer fluid is used to clean the windshield of a motor vehicle while the motor vehicle is being driven. During the warmer months of the year, the windshield washer fluid is used primarily to remove insect matter, dirt and debris. During the colder months of the year, the windshield washer fluid is used primarily to de-ice the windshield and to remove salt residue. Windshield washer fluid is typically a water-based mixture that may contain one or more water-soluble alcohols to depress the freezing point of the mixture and detergents or surfactants to increase the cleaning efficiency of the solution.
Motor vehicle service centers, such as oil change centers, vehicle maintenance garages, or automobile dealership maintenance facilities, typically purchase bulk quantities of windshield washer liquid concentrates and mix these concentrates with water at the individual facilities to produce the windshield washer liquid that is dispensed into motor vehicles as they are being serviced. Purchasing bulk quantities of windshield washer liquid concentrates results in substantial savings in material costs, shipment costs, and storage costs compared to purchasing pre-mixed windshield washer liquid.
Windshield washer liquid concentrates are typically mixed with water in a storage tank prior to being dispensed into the motor vehicles. In some cases, a measured quantity of concentrate is manually added to a storage container and the container is manually filled with water to create the concentrate/water mixture. With this type of system, the resulting liquid may be less than uniformly mixed and the quantity of concentrate required to produce a given concentrate/water ratio will have to be determined each time if the container is not empty when the mixture is being prepared. It is advantageous, of course, to have pre-mixed windshield washer fluid on hand at all times and not to completely empty the container between fillings. The containers used with manual mixing are often large, such as 550 gallon capacity tanks, and these tanks take up significant floor space.
A better system for mixing the water and windshield washer liquid concentrates utilizes a device called an eductor. The eductor has two inlet ports, one for the primary liquid being mixed, such as water, and the other for the secondary liquid being mixed, such as windshield washer liquid detergent concentrate, and a single outlet port for the mixture of these liquids. When the primary liquid flows from its inlet port to the outlet port, the venturi effect creates a suction force at the secondary liquid inlet port. This suction force causes a regular, metered amount of the secondary liquid to mix with the primary liquid within the educator and to exit the outlet port. Eductors often have replaceable or adjustable metering tips which allow the secondary liquid flow to be regulated and thereby allow the primary liquid/secondary liquid ratio of the output mixture to be varied.
In many parts of the United States, service centers use two distinctly different formulations of windshield washer liquid, a warm weather mix and a cold weather mix. The warm weather mix typically consists of a relatively small proportion of concentrated detergent and relatively large amount of water. The warm weather formulation is optimized to effectively remove the types of windshield contaminates common during warmer weather, such as insect matter, dirt and debris.
The cold weather mix typically consists of a substantial proportion of water-soluble alcohols, a smaller proportion of detergent, and water. As discussed above, water-soluble alcohols, such as methanol, ethanol, propanol, and ethylene glycol, are primarily used to depress the freezing point of the solution. It is critical to avoid having the windshield washer fluid freeze within the vehicle during the coldest months of the year. The windshield washer fluid dispensing system is a critical safety component in a motor vehicle because it allows the vehicle operator to clean the windshield if visibility becomes impaired while the motor vehicle is being driven. The dispensing system cannot perform this essential function if ice crystals form in the windshield washer fluid and clog the tubing or orifices of the dispensing system. The components of the dispensing system can also be damaged or destroyed if the windshield washer fluid becomes frozen. The cold weather formulation is therefore designed to prevent the freezing of the windshield washer fluid, even under the most extremely cold conditions likely to be encountered by the vehicle.
The amount of water-soluble alcohol in the windshield washer liquid mixture may be varied depending on the season. A ten percent (10%) methanol mixture may be acceptable for solutions dispensed in the early fall and the late winter, but a late fall or early winter mixture may require a twenty-five percent (25%) methanol mixture. Cold weather formulations may contain up to forty percent (40%) methanol. As discussed above, a warm weather formulation dispensed during the spring or summer may not include any methanol or other water-soluble alcohol.
To produce the cold weather windshield washer liquid formulation, a relatively large proportion of water-soluble alcohol and a relatively small proportion of detergent must be added to water. If an eductor is used to produce the cold weather mixture, the eductor used to mix the alcohol and water must be a high volume eductor (i.e. it must be capable of admixing relatively large quantities of alcohol with the water passing through the eductor), in contrast to the high concentrate eductor used to produce the warm weather windshield washer liquid mixture, which is only required to admix relatively small quantities of warm weather concentrate with the water passing through the eductor. A high volume educator can be used to produce an alcohol/water mixture that contains as much as 40% alcohol, while a high concentrate eductor may be used to produce a detergent/water mixture where the detergent may be diluted at a 1200 to 1, or even higher, ratio.
While premixed cold weather concentrates may be purchased that contain blended alcohol and detergent, it is typically more cost effective to purchase separate bulk containers of alcohol and detergent. Purchasing separate containers of alcohol and detergent also allows the alcohol concentration and detergent concentration in the cold weather mixture to be individually set by the operator of the mixing system.
Facilities that mix their own windshield washer fluid from concentrate and that alternate between using a warm weather formulation and a cold weather formulation have not, heretofore, had automatic mixing equipment designed to be capable of quickly and easily switching from a warm weather mode of operation to a cold weather mode of operation, and vice versa.
The inventive system allows two distinctly different types of windshield washer fluid mixtures to be produced and allows the type of mixture produced by the system to be changed merely by repositioning the handles on a pair of three way valves.
A three way water valve is connected to pair of eductors, a first high concentrate eductor that is used to produce the warm weather mixture and a high volume eductor that is used to produce the cold weather mixture. A three way detergent valve is connected to the first high concentrate eductor used to produce the warm weather mixture and to a second high concentrate eductor that mixes the detergent with the alcohol before the alcohol/detergent mixture is mixed with water in the high volume eductor to produce the cold weather mixture. Each of the eductors have metering tips which allow the ratio of primary liquid to secondary liquid to be regulated. The alcohol feed line also incorporates a metering valve which allows the composition of the winter weather mixture to be further regulated.
The three way water valve is connected to a water supply pipe having a shutoff valve that allows or prohibits water from entering the system, a float valve that maintains a constant level of windshield washer liquid within the holding tank, and a check valve that prevents detergent or alcohol from entering the water supply pipe.
The three way valves are located within a housing that acts as a holding tank for the mixture discharged from the eductors. A drain located on the bottom of the holding tank is connected to a pump which pumps the windshield washer liquid to a servicing locating where it can be dispensed into the windshield washer liquid reservoirs of motor vehicles. The alcohol feed line is connected by a supply line that terminates at the bottom of a sealed alcohol container. A vent pipe connects the headspace on the top of the alcohol container to the headspace on the top of the housing. A passageway allows the vapors in the headspace of the housing to pass through an activated charcoal filter before they escape the system. The vent pipe allows air to enter the sealed alcohol container as the level of alcohol in the container drops and allows fumes from the alcohol to reach the activated charcoal filter, where they can be neutralized before being discharged into the building in which the system is located. A removable cover inhibits evaporation when the cover is in the closed position and allows an operator to access the internal components of the system to reposition the handles of the three way valves, to adjust the metering valve, or to replace the metering tips when the cover is in the open position.
In use, the level of windshield washer liquid in the holding tank is regulated by the float valve and the holding tank is automatically refilled as the windshield washing fluid is dispensed. When the detergent or alcohol containers being used are emptied, the operator merely removes the applicable supply line (and the vent pipe in the case of the alcohol container), removes the empty container, places a full container of detergent or alcohol in the proper position and reconnects the supply line (and the vent pipe in the case of the alcohol container). If the metering tips and the metering valve connected to the educters are properly adjusted, the only action required to switch the system from the summer mode to the winter mode, or vice versa, is to reposition the handles on the three way water valve and the three way detergent valve to the opposite positions and to make sure that the appropriate containers are properly connected to the system.
The preferred embodiment of the disclosed system withdraws the detergent and alcohol and produces windshield washer liquid utilizing only the hydraulic force of the water entering the housing from the water supply line. An air driven pump is used to pump the windshield washer liquid to the appropriate dispensing locations, which allows the inventive system to mix and dispense windshield washer liquid without the use of electrical motors or electrical circuits. This is particularly advantageous because many alcohols that can be used to produce the cold weather mixture, such as methanol, are flammable and eliminating electrical motors and electrical circuits eliminates possible ignition sources.
Further objects, features and advantages of the invention will become apparent from a consideration of the following description when taken in connection with the accompanying drawing.